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FreeBSD-SA-22:02.wifi                                       Security Advisory
                                                          The FreeBSD Project

Topic:          Multiple WiFi issues

Category:       core
Module:         net80211
Announced:      2022-03-15
Affects:        FreeBSD 12.x and FreeBSD 13.0
Corrected:      2021-11-19 00:01:25 UTC (stable/13, 13.0-STABLE)
                2022-03-15 17:45:36 UTC (releng/13.0, 13.0-RELEASE-p8)
                2022-02-15 16:05:49 UTC (stable/12, 12.3-STABLE)
                2022-03-15 18:18:08 UTC (releng/12.3, 12.3-RELEASE-p3)
                2022-03-15 18:17:30 UTC (releng/12.2, 12.2-RELEASE-p14)
CVE Name:       CVE-2020-26147, CVE-2020-24588, CVE-2020-26144

Note: This issue is already fixed in FreeBSD 13.1-BETA1.

For general information regarding FreeBSD Security Advisories,
including descriptions of the fields above, security branches, and the
following sections, please visit <URL:https://security.FreeBSD.org/>.

I.   Background

FreeBSD's net80211 kernel subsystem provides infrastructure and drivers
for IEEE 802.11 wireless (Wi-Fi) communications.

II.  Problem Description

The paper "Fragment and Forge: Breaking Wi-Fi Through Frame Aggregation and
Fragmentation" reported a number of security vulnerabilities in 802.11
specification related to frame aggregation and fragmentation.

Additionally, FreeBSD 12.x missed length validation of SSIDs and Information
Elements (IEs).

III. Impact

As reported on the FragAttacks website, the "design flaws are hard to abuse
because doing so requires user interaction or is only possible when using
uncommon network settings."  Under suitable conditions an attacker may be
able to extract sensitive data or inject data.

IV.  Workaround

No workaround is available, but the ability to extract or inject data is
mitigated by the use of application (e.g. HTTPS) or transport (e.g. TLS,
IPSEC) layer encryption.

V.   Solution

Upgrade your vulnerable system to a supported FreeBSD stable or
release / security branch (releng) dated after the correction date,
and reboot.

Perform one of the following:

1) To update your vulnerable system via a binary patch:

Systems running a RELEASE version of FreeBSD on the amd64, i386, or
(on FreeBSD 13 and later) arm64 platforms can be updated via the
freebsd-update(8) utility:

# freebsd-update fetch
# freebsd-update install
# shutdown -r +10min "Rebooting for a security update"

2) To update your vulnerable system via a source code patch:

The following patches have been verified to apply to the applicable
FreeBSD release branches.

a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.

[FreeBSD 13.0]
# fetch https://security.FreeBSD.org/patches/SA-22:02/wifi.13.patch
# fetch https://security.FreeBSD.org/patches/SA-22:02/wifi.13.patch.asc
# gpg --verify wifi.13.patch.asc

[FreeBSD 12.x]
# fetch https://security.FreeBSD.org/patches/SA-22:02/wifi.12.patch
# fetch https://security.FreeBSD.org/patches/SA-22:02/wifi.12.patch.asc
# gpg --verify wifi.12.patch.asc

b) Apply the patch.  Execute the following commands as root:

# cd /usr/src
# patch < /path/to/patch

c) Recompile your kernel as described in
<URL:https://www.FreeBSD.org/handbook/kernelconfig.html> and reboot the
system.

VI.  Correction details

This issue is corrected by the corresponding Git commit hash or Subversion
revision number in the following stable and release branches:

Branch/path                             Hash                     Revision
- -------------------------------------------------------------------------
stable/13/                              6acb9d5f955b    stable/13-n248098
releng/13.0/                            0d1db5c3257e  releng/13.0-n244782
stable/12/                                                        r371640
releng/12.3/                                                      r371748
releng/12.2/                                                      r371740
- -------------------------------------------------------------------------

For FreeBSD 13 and later:

Run the following command to see which files were modified by a
particular commit:

# git show --stat <commit hash>

Or visit the following URL, replacing NNNNNN with the hash:

<URL:https://cgit.freebsd.org/src/commit/?id=NNNNNN>

To determine the commit count in a working tree (for comparison against
nNNNNNN in the table above), run:

# git rev-list --count --first-parent HEAD

For FreeBSD 12 and earlier:

Run the following command to see which files were modified by a particular
revision, replacing NNNNNN with the revision number:

# svn diff -cNNNNNN --summarize svn://svn.freebsd.org/base

Or visit the following URL, replacing NNNNNN with the revision number:

<URL:https://svnweb.freebsd.org/base?view=revision&revision=NNNNNN>

VII. References

<URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-26147>
<URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-24588>
<URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-26144>
<URL:https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=254737>
<URL:https://www.fragattacks.com/>

The latest revision of this advisory is available at
<URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-22:02.wifi.asc>
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